John Lazar / AP

Phil Mickelson pumps his fist after an eagle. Mickelson won the Northern Trust Open tournament on Sunday.

updated 6:49 p.m. ET Feb. 22, 2009

LOS ANGELES - Phil Mickelson nearly blew the biggest lead of his career, then had to scramble for par to avoid a playoff.

When his roller-coast week at Riviera ended Sunday, the Northern Trust Open turned out to be one of his more satisfying victories.

After watching tee shots sail in every direction, turning a four-shot lead into a two-shot deficit with three holes to play, Mickelson recovered with back-to-back birdies and stepped to the 18th tee with a one-shot lead .

Then, he had to bury some demons.

Two years ago, Mickelson had a one-shot lead until making a sloppy bogey on the historic finishing hole and losing in a playoff. This time, he poured his tee shot down the middle of the fairway and two-putted for par from 60 feet, making a tough 6-footer for the win.

“I’ll take a lot out of this,” Mickelson said after closing with a 1-over 72. “To be able to heart it out on 16 and 17 with two birdies, then to make that par on 18 when two years ago I didn’t, that meant a lot to me.”

So ended his West Coast Slump.

Mickelson arrived at Riviera having failed to crack the top 20 in his first three tournaments, missing the cut in Phoenix and making it on the number with a birdie on the last hole at Pebble Beach.

But when one of his wildest weeks was over — 63-72-62-72 — Lefty won for the 35th time in his career, with 17 of those victories on the Left Coast.

He finished at 15-under 269 and joined Ben Hogan, Corey Pavin and Mike Weir as the only back-to-back winners at Riviera.

“I’m pleased to be sitting here as the champion,” Mickelson said. “And it was not easy. I had a five-shot lead and I let it slide. The good thing was that I was able to fight hard. Even though I didn’t have my best stuff, I was able to fight through it.”

It was the first time since the 2005 PGA Championship that he won without breaking par in the last round.

Stricker closed with a 67 and was on his way to the range to get ready for a playoff when he saw Mickelson leave himself a tough par putt on the final hole, and stopped when he heard the cheer.

He had his chances. Stricker missed a 12-foot birdie putt on the par-5 17th that would have given him a three-shot lead at the time, then missed a 12-footer for par on the 18th.

It was the second time on the West Coast that Stricker had a chance to win. He had a three-shot lead at the Bob Hope Chrysler Classic until he was blown away by the raging desert wind, closing with a 77.

“It’s just a little disappointing when you don’t finish it off, or have the opportunity to finish it off,” he said. “And I didn’t.”

But the real heartache belonged to Fred Couples.

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A two-time winner at Riviera, his favorite golf course west of Augusta National, the 49-year-old had a chance for one last victory in his final full season on the PGA Tour. Couples was one shot behind when he fanned his approach to the 18th green and watched in disgust as it struck a eucalyptus tree. He finished with a bogey for a 69 to tie for third with K.J. Choi (69) and Andres Romero (70).

Couples learned earlier in the week that his estranged wife, Thais Baker, died Tuesday of breast cancer. They never divorced after splitting up nearly four years ago, and Couples said he is not welcome in their home in Santa Barbara.

“She was a nice person,” he said. “She did everything she could to make it another month.”

Mickelson had never lost a PGA Tour event when leading by more than four shots going into the final round, but what could have been his biggest collapse turned into a stunning recovery.